Duty cycle is measured by dividing the rising part of a signal cycle by the full length of the signal cycle. The duty cycle of a signal may get distorted due to ground shift or noise during the communication. If the absolute average duty cycle distortion is greater than a threshold, a communication failure may occur. For example, a distortion in the range of 30% or more may be beyond the tolerance for many signal decoding circuits and may result in a higher than desirable bit-error rate.